Maximum likelihood tree of Brazilian subclade F1 strains and reference strains inferred from nearly full-length HIV-1 sequences. Black circles show the newly sampled strains from Brazil. Nucleotide sequences were compared with reference sequences of subtype A-D, F-H, J and K http://hiv-web.lanl.gov. For clarity purposes, the tree was midpoint rooted. The approximate likelihood-ratio test (aLRT) values of ≥ 70% are indicated at nodes. The scale bar represents 0.05 nucleotide substitution per site.